Lämpösaareita

Lämpösaareita, or heat islands, are urban areas that are significantly warmer than their surrounding rural areas. This temperature difference is primarily caused by human activities and the built environment. Cities tend to have more surfaces that absorb and retain heat, such as asphalt and concrete, compared to the vegetated landscapes found in rural areas. These surfaces absorb solar radiation during the day and release it slowly at night, leading to higher temperatures.

Another contributing factor is the lack of vegetation in urban settings. Trees and green spaces provide shade and release water vapor through evapotranspiration, which has a cooling effect. When these are replaced by buildings and paved surfaces, this natural cooling mechanism is reduced. Additionally, waste heat generated by human activities, such as vehicle emissions, industrial processes, and air conditioning systems, also contributes to the urban heat island effect.

The consequences of heat islands can be substantial. They can increase energy consumption as more electricity is needed for cooling. They can also exacerbate air pollution and negatively impact human health, particularly during heat waves, leading to heat-related illnesses and mortality. The effect is most pronounced during the summer months and at night. Mitigation strategies include increasing green spaces, using reflective materials for roofs and pavements, and improving urban planning to incorporate more natural cooling elements.